Double-screw jack



May 20, 1930. A. JOHNSON DOUBLE SCREW JACK 2 Sheets-Sheet 2 Filed Oct. 19, 1926 7-" 4:247:15. fill/2J0);

Patented May 20,1930

* NITEDI TATE MESNE ASSIGNMENTS, To WALKER MAnUFAc'r n-me ocrarnmzgor Racine. .wIs-

consrn. A CORPORATION;QF'WISCONSIN' DOUBLE-SCREW; JACK I Application filed hotel er 1a, 1926. Serial No. 142,723.

This invention relates tothe type'of jack which is the subjectmatter of my Patent No. 1,535,727 issued April 28, 1925, and it involves all the advantagesofthesaid jack.

The principal, other objects "of the inven tion are to eliminate, the latch construction shown infsaid patentand the corresponding projection on the casing provided-therefor and to secure the same'res'ults withoutthe useof this feature; to provide a jack ofthat type with means whereby the inner screw ,willbe brought down to itslo'west level in the operationof' loweringfthe'iouter screw without, reference to the load onthe jack, in other words to make it doublefacting as to both screws and to provide this means in such formthat it will add very little to the,

mechanism of the jack shown in the said patent; a d to provide the j ack with an anticas ng and guides;

friction bearing'without interfering With the means for causing the jackfto reverse at either end of its stroke, and n general to simplify theconstruction.

Other ob'ec-ts' and advantages of the invention will appear hereinafter.

, Reference isto be had to the accompanying drawings in which Fig. 1 is a 'central'vertica1sectional view, with parts'in section, of a 1acker'nbody1ng this invention, [constructed in a simple form 'Fig. 2 is a'horizontal sectional. View of the same on the line 2-2 of Fig. 1; Fig. 3 is a sectional'viewsimilar to Fig. of the inside of the casingwith the screws removed to illustrate the construction of the Fig. l is a sectlonal view showing the,

5* Fig. 8' is-a sectional view of thejack show- ,Fig. 7; an'd Figs. 10 and 11 are horizontalsectionalB lings it"will be seen that thisj ack involves most of the features of the j ack shown'in the above dentified patent comprising the casing 'ing screws raised to their limiting position" 9:15? a sectional V of 15119 interior the Jack casing the pfl f' of with the;

PATENT OFFICE i ALVIN L. 'JOHNSON, or WORCESTER, MAssAcHnsErrrs, Assirernon,v BY nmnorueiwn screws removed, taken on the line 9 9" "cif."'

views on the "lines 1010' and" respec tivel'y of Fig. 8.

Referring first to the first sheet of draW-,

10 with the passagell'jthrough itand the steel disc 12 closing. the bottom of thejack.

The cylindrical passage 11 'upthrou gh the casingis provided with a, plurality of'longitudinal guides 13 extending from near-the "bottom to near the top ofthe passage. 'jThese guides are provided, at the-top and bottom r spectively, with slanting ends"13;and 13 for the same purpose as'in thesaid atent; 7

Inside th'e passage is a left handed'square threaded screw 15 having across 1111 15 at the bottom thereof, .Instead of being-fixed 1n the screw, as shown in said patent, this v,

pinis adapted to be shifted verticallyand 'for that reason is mounted in verticalslo ts 14 which allow the pin to shift up and down.

This pin drops to the bottom of these sages by gravity as shown in Figs. and5 and is raised in them when it reaches the bottom of its stroke by engaging a central vertical spring .24 on the disc 12 as shown 1n Fig. 1. This brings it'into contact with a surface 13 so'that it will either ratohetover it'ormove up along two opposite'guides ac- ;cording to the direction of, rotation.

.At the top of the casing is provideda cir cularspace 17 for receiving this pinasin the a shoulder on the casing and supporting the nut 18 which engages withthe thread of. the

screw 15 for operating it. This. nut can be 'operated in any desired way but Ihaveshown an integral gear 19 on it meshing with the pinion 20 on the operatinglshaftfll'. On the :other case and above the space is a ball or other anti-friction bearing23 supported by top of the casing is the cover 22 takingithe thrust of thenut as in the above mentioned patent except-that this cover is simplified a little by making it a fiat'plate;

Inside the hollow'screw 15, which is screw 1 c threaded with'a left hand square thread, is

the inner screw 28'provided with a'work rest 29 which is fixed positively to itfor support- 7 ing the load which is indicated as a part 80 i of an automobile. .[It willbenoticed that the latches shown inthe above'mentioned patent lot h P j t t nd ne essitate the provision" of an engagement on'the cas'ing'ii are eliminated. V v r QTheoperation is very simple.

-outer screw reaches the-bottom ofits stroke, the pin l6 will rest on thespring'24 which constitutes a; yielding' means for holding the hen I Qcro'ss up. Thisipin ratchets overthe hottoms of the-guides 13, namely the surfaces 13*, when the screw is rotated in one direction.

hasstarted,itstaysinthat position and the tle, the spring will .no longer support it; and

itwilll be restricted iby' the slots ltand Will so i I led-When rotated in the direction to raise it it 1 will engage the projecting surface of one ofthe guides immediately After the screw in moves to'the position shown inFi'g; 3. 11st as soon as ithas moved upwardlyalit drop down to the bottom'of these slots. However, it" will continue to prevent the screw from turning with thenut18. Consequently the Continued rotation. ofthe nut in that direction will raise the outer screw, carrying with it the inner screw wh ch may be assumed to have been adj ustedby hand previously up ward substantially into contact with the load 30. The continued rotation of thenut will 'raisethe outer screw to its limiting position showninFig." 5. Then'the pin 16 will ratchet over theslanting'surfaces 13Pand the outer screw willautoinaticallyl and immediately commence toturn-YAs the'innerscrew is held :againstturningsby' thefix e d head 29 engag ing the load tobe lifted, the trotation ot theoliter screw will then cause the inner screw to rise duringthe rest of the rotation of the nut 18 in the same direction.v It will be noted that r y no change in operation is necessitated on t-he "part of the operator and he hardly notices that any change is-takingplace in the opera-U tion of thefjack, Intact, unless heis mechanically 'inclined" he will never know it at'all.

' After the load is raised to the desiredlp'osis it tionthe threads of the screwsjhold it there so that it cannotldescendof its own accord.

}When it is desired atelower'itQthe nut is rotated in the'opposit'e direction; the eiiect "of which is first to bring the pin 16,Iwhich is at the bottom ofthe slots 14, immediately into contactwith the'projecting'edges oftwo opposite guides '13; The outer screwgcan rotate only a very small part oi'ja revolution before it stops rotating and Commences todescend by the rotation'of the nut 18.; The outer screw as'goes down without rotating and takes the inner screw with it also without rotating after 1,759,621 v l i the work rest-29com es down out Contact with the load30. Then the load is freed iroin the jack and the jack can be taken out.

It will be understood that this is a'practical 'operation inthe raising of an'automobile'havmg a fiat tire and the lowering of itwhena new tire is put-:onor the old tire blown up/ p The car doesnot have to come down beyond thetposition from which it was started IWltlf-I out a-load. ,Furthermoreif it did, that could be accomplished by starting the raising ofthe load with the outer screw raised a short dis- 'tanceout of the casing at-the he'ginning of the operation;

t f It will be seen that this simplifies the con- 1 V structiori' of'the' jaclr shown in said-patent,

particularly in-the nianufacture'o'f thecasin'g '10which can'be made cylindrical [from the baseto't-he'top' Any uncertainty, dueto the;

nated because there is a ch'a'nce'to use alar'ger latches'shown in saidpatent; isalso elimiQ v spring 24 and a moredurable' one in positioni without enlarging the j ack,v Also by'thisare 5 rangenient aplace is provided for the ,ball" bearing 28 to take the weight of the whole load through the nut 18 and thus improve the operationand reduce the friction. It-willbe seen thattliis ball bearing comes at a point: where the ratchet mechanism isshowninmv prior-patent anddocsnot subtract anythingjg ii from the travelof the-outer screw; 1

. The invention' can be carried; out in the iorm shown in the second sheet of'the draws ings. In this case the numerals 10, 11,12 13', V 13*, 13 15, 16, 18, 19,20, 21,.22, 28 and 30 are arranged exactly in the same wayf'and refer to'exactly the same partsas'in the first I V i[ ii sheet. In this case,'liowever, the'inner screw" 28, which is solid in the otherii'orm is'hollow,

throughoutmost of its length and provided with a square passagethroughimotherwise solid bottom for j receiving a square rod'31."

but is slidablyaconn'ected with it through a This rodenters a squareholeina plate 25*at r V the hottoinand is headed over on the bottom J and top so that itfcannot come up out ofit "square passage "in it. This'pl'ate 25'has "opposite projections 26 which constitute guide pins. and they enter slots 27 extending,

tationwith respect to This. plate 16* is T providedwith, opposite projections which constitute thecross pin 16 shown onthe first [sheet and this pin 16cooperateswithfthe; guides 13 in the same way asi'shown onthe,

other sheet.

Herethe operation is the sanie therod 31, which isheaded over atithetop, V so that it will not'drop 'down through the screw' is positively guided by the pins 26 in the guides 27 "and is kept fromirotationl The rest 29' can be swivell'edi It will be rememberedthat inthe other the screw 15 at practically thesame height at which it started, it can bedrawn down into it by the continued rotation of'the'shatt 21 until it reaches its lowermost-position;

In'theoperatio'n ofthe jack shown on sheet 2,-everything is practically the same as inthe. other case'with the exceptions noted. The

nut 18"is rotatedby the shaft 21 to-raise the outer screw from the bottom and the spring- 24 causes the pins 16 to engage the guides 13 and prevent fthe outer screw from rotating at the beginning o'fthestroke and throughout the same until it reaches the top. But in this case the screw 28, which cannot rotate, is

positively carriedup by the outer screw, having the same relative position to it all the time. When" the outer screw reaches its limiting position and rotates, the pins 26 are guided upward in the guides-'27 thus P81111111: ting thejscrev'v -28-to rise'all the way out oi the screw 15.

Now in this case allthe advantages obtained by the construction shown in the patent andbythat shown on Sheet 1 ll'lillllS case are obtained 'an'd'this additional advantage also,

which has'been explained. I

Although I have illustrated and described only two forms of theinvention I-an'i-aware of the fact'tha't other modifications can be made therein by any person; skilled in the artwithoutjdeparting from the scope oi the invention as expressed in the claims. There fore 'I 'donot wishto be limited ii -these respects, but what Ido claim is:

1. BI'na double screw, jack,the combination with two screws, one threaded Wltl'llll the -other,-of a casing having guides along its 1nterior,=a rotatable nut engaging the threads ofthe outer screw to operate it, means projecting from the 'outerqscrew and movable vertically with respect theretofor engaging "the guidesto prevent'the outer screw from turning, and means'for forcing said pro ecting means into the spacesbetween theguides.

2. 'In-a double screw jack, the combination with two screws of thesame hand, one thread- I ed Within the other, ofa vertical casing having a series otguides along its interior, a rotatable nut engaging the threadsof the outer screw to operate it, relatively movable means projecting. from the outer "screw at the bottom for engaging the' guides to prefvent the outer screwfrom turning, and means "for yieldingly forcing saidp'ro ecting means "outer screw.

screw is in its lowermost position.

up iiito the spacesibetween the bottoms of the 1 guides when the outer 3. In a double screw 'jackJthe combination I withthe two screws, one within the other,'and

means for rotating them, of a casing having a series of guides in the interiorprovided with slanting suriaces at their lower ends, sa d surfaces all slanting in the same direction aroundv the casing, apin projecting from thescrew and adapted to move along the slanting end surface of anyguide andthen into the. guide :to prevent the screwfrom turning, said pin being movable" along the screw, and yielding means under it for forcingthe' pinv into the withdrawn into the'casing. V

fl. In a double screw jack, the combination with the two screws, one within theiother,

and means for rotating them, of a casing having a pluralityof vertical guides .alongthe interiorprovided with slanting'surfa'ces at both ends, a pin projecting from-the screw and adapted to move along the slantingend suriace' of a guide and then into the guideto prevent the screw from turning, and a-sprin'g spaces between the guides whenthe screw is for moving. the pin vertically and guiding-it 7 into one of the guides.

5. In a double screw'jack, the combination with twoscrews, one within the other, and

meansfor rotating the outer one, ofa' casing having guides extending along 1t inside, each screw adapted to be received in said spaces and to move over one of said slanting surfaces providedwitha slanting surface-at the end, the casing also havingspaces aroundit atathe ends of said guides, a pro ectlon on the outer aIid along therguide, and'means formovingthe projection vertically with respect to the outer screw to aposition to guide it along one of the guides and preventrotation of the 6. Ina double screw ja'clnthe combination with two screws onethreaded-in th'e other,

and means'for rotating one'of them to raise it "or lower "it, of a casing for supporting the screws, aplurality of guides for preventing the rotation of OnescreW When-it is'being" raised or lowered, said; guides-'having slantends to permit oftheir becoming efiective for the purpose specifiedat all points aroundthe circumference and a vertically and freely movable cross pin carried by the screw for starting "the screw to move longitudinal-ly.

7 In a" double screwjaclr, the combination -w1th two screws, one threaded withinthe other, a casing, a rotatable int'eriorl'y threaded 2 member engaging thefthreads of theouter screw for raising and lowering it, the outer screw having longitudinal slots, a radial-pin movable in said slotsand adapted roman;

the bottoms thereof by gravity, means in'th e casing for engaging the ends ofsaidv pin to prevent the turning of the outer screw, said I b "means terminating short o'f'the topandbottom ofthecasing, and means forraising the pin, when the screw reaches the bottom of the casing, so as to engagesaid means.

8; In a double screw jack, the combination with two screws, one threaded within: the other,-a casing, a rotatable interlor-ly threaded member engaging the threads ofjtheouter .screw for raising and lowering it, the outer screw having longitudinal slots, a radial pin V movable in said slots and adapted to rest.

atthe bottoms thereof by'gravity, means'in the'CaS1ng for engaging-the ends of said p n to prevent the turning-of the outer screw,

said m'eans terminating short of the top and bottom of the casing, and a, central spring for lifting thepin "when the outer screw is entirely, withdrawn into the caslng. 9. 111 a double screw jack, the combination -with two screws, one threaded within theother, a casing, a rotatable interiorly threaded member engaging the threads of vthe outer screw for raising: and I lowering it, "the-outer screw having longitudinal slots, a radial pin 25" movable in said slots andadapted to rest-atthe bottoms thereof by gravity, longitudinal guidesjin the casing, said pin being adapted to engage said guides andfpreventmg the rotationofth'e outer screw,and a spring for lifting'said pin into engagement with the guides.

.i 10In1a doublescrew jack; the combination with two screws,one threaded within the 7 othenia casing, a rotatable interiorly threaded 'member engaging the, threads of the-outer J35 screw for. raising. and lowering it, the outer screwhaving longitud nal slots, aplate at rotatably connected with said rodand having plate for raising theupper plate, when;the

outer screw reaches the bottom of the casing.

' 11. In, a double screw j ack, t he combina a tionwith tw'o screws, one threaded within the other, .a casing, 'means for'raisingiand lowering the outer sorey'v', the screw having a passageithrough' 1t witha' non-circulargho'le in thebottom,a non-circular rod slid- -ingly fitting in said hole,means in the casing for preventingf the non-circular rod from turning at allltimes, means inthe casing for preventing the outer screw from'turning until it reaches the end of its travel, and a spring between; said means for forcing the last named means intozoperati've position when .the outer screw] reaches its lowermost position.

able vertically with V 12. Ina double screw jack-, the combination with two-screws, onethreadedwithini the other, of a casinghaving Ineansfor guiding the outer screw, a rotatable nut engaging screw. 13..- In a lifting jack, the combination with two screws one threadedfwithin the other, of a casing having substantially vertical guides 1 the threads of: the outer screwto raise or low-5,. er it, and a pin extending through the'outer I screw to engage the guidingjmeansfandshifta L V respect tosaid outer therein with beveled upper ends, a rotatable nutsupported by the casing and engagingthe -e threads oftheouterscrew to operate it, and"; means pro ect1ng from the outer screw into engagement with theiguides, and vertically movable with respectto theouterscrew. v

14. In a lifting jack, the combination as two screws, onethreadecbwithin the other,

of a casing having sub'stantiallygvertical guides therein with 'beveled lupper ends, a

"rotatable nut supported bythe casing and engaging thethreadsof the outer screw to operate it, therebeing vertically elongated slots in the sides of the'lowerend, portion ,of t

the outer screw, and a-pin resting in these" V slots and projecting at'its ,endsintoenga gement with theguides. i 1 l5. Ina lifting .jack,the combination-with two screws, one threaded withinithe othenof. a casing having substantially vertical guides therein with beveled upper ends, a rotatable nut supported by the casing and'engagingthe threads of'the outer screw to operate" it, and'af pin adapted to e'ngagethe guides atits ends e and looselysupported by thelower end ofthe outer screw so that, it'rnay move vertically with respect thereto.

16., In a lifting jack, the combination with? two screws,one"threadedwithin the other, of h a casing having substantiallyvertical guides-f 5; therein with beveledupperl and lower, ends,

a rotatable nut supported by the casing' and i r engaging the threads of the"outerv screw to operate 1t, there'being vertically. elongated slots in'the sidesof the lowerend' portion of:

the outer screw, and a. pin resting ingthese slots and projecting its 'endsvinto engage-1' mentwith the guides, means engagingboth the inner screw and the vcasing forpreventtion of the last named means.

f17. In a lifting jack,the'combin'ation ing rotation of the inner screwwithoutinten, V ferlng "with 1ts vertical movement: and :a p 7 spring interposed between the pin and a por two screws, one threaded within the other ofi rotatable nut supported by the "casing'and;

a casing having substantially?verticalguides i therein with beveled upper and lower ends, a

engaging the threads of the outer screwf'to '7 operate it, and apin adapted to engage the; g i guides at its endsand loosely supported bythe" r lower end of thejouter screwso that it may Y move vertically with respect:thereto,ineans engaging both the inner ser ew and the casing for preventing rot ation of the inner screw- Without interfering with its Vertical movement and a spring interposedbetween the 5 pin and a portion of. the last named means,

In testimony wh ereof Ihave hereunto af- LVIN L. JOHNSON. 

